Hydraulic starter drive



Sept. 29, 1953 A. C. JENNY HYDRAULIC STARTER DRIVE Filed Dec. 21, 1.948

INVENTOR. ALBERT C; Jzmvy Patented Sept. 29, 1953 2,653,577 HYDRAULIC STARTER DRIVE Albert C. Jenny, Cleveland, Ohio, assignor, by mesne assignments, to Hydraulic Systems, Inc., Cleveland, Ohio, a corporation of Ohio Application December 21, 1948, Serial No. 66,465

4 Claims.

This invention relates to hydraulic starters and more particularly to the rotating cylinder and reciprocating piston type of motor for hydraulic starters.

In starter drives of this general type, it is conventional practice to so construct and arrange the motor, drive and porting plate as to extend the starter pinion to be in mesh with the flywheel ring gear prior to rotation of the drive shaft and to then suddenly initiate a full speed rotation of the motor and drive thereby of the drive shaft.

Such an arrangement imposes sudden shocks and torques that are detrimental to the starter, drive and motor.

It is therefore one of the primary objects of the invention to provide in such a device a metering means for the hydraulic system whereby as the pinion is being extended, the drive shaft will be slowly rotated until the pinion and ring gear are partially meshed, at which time full flow of hydraulic fluid to the motor is permitted so as to obtain full speed rotation of the motor and drive shaft. The object of this is two-fold in assuring proper meshing in avoiding teeth hitting head-on and in decreasing the shock and torque attending the full speed rotation of the motor and drive shaft.

With the foregoing and other objects in view, the invention resides in the combination of parts and in the details of construction hereinafter set forth in the following specification and appended claims, certain embodiments thereof being illustrated in the accompanying drawings, in which:

Figure 1 is a view in longitudinal section taken through the starter assembly, and, with respect to the porting plate, taken along line ll of Figure 2; and

Figure 2 is an end view of the porting plate.

Referring more particularly to the drawings, a starter l is shown consisting essentially of an engaging head casing 2, a port plate 3, and a motor casing 4. Suitable bolts may be employed to secure casing 2, port plate 3, and casing 4 together. Positioned axially within the starter l is a rotatable shaft 6 which is carried at one end in a bearing sleeve 40 of casing 2 and at the other end by a bearing sleeve 8.

A wobble plate 9 is carried between shoulders I!) and H of casing 4 by means of a ball bearing assembly I2. The plate 9 is press fitted to the inner race l3 while the outer race I4 is press fitted between shoulders l and I I.

A cylinder block I is firmly held against port plate 3 by means of compression spring It. The

spring [6 is held under compression between the shoulder I! of block 15 and a snap ring 20. A plurality of freely sliding pistons 2| is provided, one in each of the bores 22 of block l5. The cylinder block I5 is further provided with splines 23 which mate with similar splines 24 on shaft 6. Casing 2 is provided with an intake pressure port 28 which connects with an arcuate port 21 in port plate 3. An exhaust port 25 connects with an arcuate port 26 in port plate 3.

Disengaging springs 29 and 30 are provided within casing 2 about shaft 6. The spring 29 abuts against an oil seal 3| at one end and against shoulder 32 of a sleeve l at the other end. Spring 33 engages a bushing 33 at one end and an engaging pinion 34 at the other. The engaging pinion 34 is helically splined to shaft 6 and when in operation engages any suitable engine driving gear, such as a flywheel ring gear.

For a distance approximately half the length of the sleeve piston I there is provided a relatively shallow undercut ll. The actuation of the hydraulic motor is, in part, controlled by the movement of sleeve piston 1 during a starting cycle. Fluid under pressure from port 28 gets behind shoulder 31 of sleeve 1 by means of undercut section 4|. The sleeve 1 is moved to the left along shaft 6 against the action of springs 29 and. 30. During this time a small metered portion of hydraulic fluid flows through undercut 4| through port 2'! to slowly rotate the motor to slowly rotate the drive shaft 6. The pinion 34 is driven to the left under action of the sleeve 1 with a combined rotary and sliding movement due to the mating engagement with helical splines 39 on shaft 6 until an engine driving gear is partially engaged, at which time sleeve piston i has moved far enough to the left to open the port 28 fully to allow flow to port 21 in plate 3 to obtain full speed rotation of the motor and drive shaft. The pistons 2| will be actuated in the manner normal to this type of motor and the rotary motion of the shaft 6 is transmitted to the pinion 34 which engages the engine driving gear thereby starting the engine. Thus it is seen that the motor and shaft rotate slowly during pinion extension and that positive engagement of the pinion 34 with the engine driving gear is insured prior to full speed rotation of the motor and the efficiency of the starter is considerably increased thereby. Disengagement is effected by the springs 29 and 30 actuating sleeve 1 and pinion 34 to the right.

I claim:

1. An hydraulic starter comprising a rotatable drive shaft, a sleeve mounted thereon for longitudinal sliding movement thereon, said sleeve having a piston portion at its one end, a starter pinion helically splined to said shaft at the other end of said sleeve, an hydraulic motor for driving said shaft, a porting plate with an inlet and outlet port, said motor having an inlet and an outlet port, resilient means for normally maintaining said sleeve and starter pinion in retracted position, hydraulic fluid metering means for imparting hydraulic power to said sleeve to extend it and said starter pinion on said shaft to a predetermined extent while simultaneously imparting hydraulic power to said motor to rotate said shaft relatively slowly and upon further extension of said pinion to rotate said shaft at a relatively greater speed, said metering means comprising passages to lead fluid from said porting plate to a point behind said sleeve piston onthe opposite side of said resilient means and to the inlet port of said motor.

2. An hydraulic starter comprising a rotatable drive shaft, a sleeve mounted thereon for longitudinal sliding movement thereon, said sleeve having a piston portion at its one end, a starter pinion helically splined to said shaft at the other end of said sleeve, an hydraulic motor for driving said shaft, a porting plate with an inlet and outlet port, said motor having an inlet and an outlet port, resilient means for normally maintaining said sleeve and starter pinion in retracted position, hydraulic fluid metering means for imparting hydraulic power to said sleeve to extend it and said starter pinion on said shaft to a predetermined extent while simultaneously imparting hydraulic power to said motor to rotate said shaft relatively slowly and upon further extension of said pinion to rotate said shaft at a relatively greater speed, said metering means comprising an under cut in said sleeve to provide a passage to lead fluid to a point behind said sleeve piston on the opposite side of said resilient means and to the inlet port of said motor.

3. An hydraulic starter comprising a rotatable drive shaft, a sleeve mounted thereon for longitudinal sliding movement thereon, said sleeve having a piston portion at its one end, a starter pinion helically splined to said shaft at the other end of said sleeve, an hydraulic motor for driving said shaft, a porting plate with an inlet and outlet port, said motor having an inlet and an outlet port, resilient means for normally maintaining said sleeve and starter pinion in retracted position, hydraulic fluid metering means for imparting hydraulic power to said sleeve to extend it and said starter pinion on said shaft to a predetermined extent while simultaneously imparting hydraulic power to said motor to rotate said shaft relatively slowly and upon further extension of said pinion to rotate said shaft at a relatively greater speed, said metering means comprising an undercut in said sleeve throughout approximtaely half its length to provide a passage to a point behind said sleeve on the opposite side of said resilient means to extend said sleeve and to simultaneously provide a restricted metering passage for fluid to the inlet port of said motor to drive it relatively slowly.

4. An hydraulic starter comprising a rotatable drive shaft, a sleev mounted thereon for longitudinal sliding movement thereon, said sleeve having a piston portion at its one end, a starter pinion helically splined to said shaft at the other end of said sleeve, an hydraulic motor for driving said shaft, a porting plate with an inlet and outlet port, said motor having an inlet and an outlet port, resilient means for normally maintaining said sleeve and starter pinion in retracted position, hydraulic fluid metering means for imparting hydraulic power to said sleeve to extend it and said starter pinion on said shaft to a predetermined extent while simultaneously imparting hydraulic power to said motor to rotate said shaft relatively slowly and upon further extension of said pinion to rotate said shaft at a relatively greater speed, said metering means comprising an undercut in said sleeve throughout approximately half its length to provide a passage to a point behind said sleeve on the opposite side of said resilient means to extend said sleeve and to simultaneously provide a restricted metering passage for fluid to the inlet port of said motor to drive it relatively slowly until said piston has moved to a point where it opens full flow from said porting plate inlet to said inlet to said motor for driving the latter at full speed.

ALBERT C. JENNY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,163,849 Pratt Dec. 14, 1915 1,652,360 Jackson Dec. 13, 1927 2,122,816 Kissane July 5, 1938 2,144,195 Nardone Jan. 1'7, 1939 2,283,184 Coffman May 19, 1942 FOREIGN PATENTS Number Country Date 20,202 Great Britain Sept. 25, 1914 574,901 Germany Apr. 21, 1933 583,661 Germany Sept. 7, 1933 

